Hemodynamic Disorders Martino
A 72-year-old man is dead on arrival after collapsing at home. Renal cortical infarcts are noted at autopsy. A section through the arcuate artery is shown. Which of the following is the most likely source of the atheroembolus occluding this artery? (A) Abdominalaorta (B) Common carotid artery (C) Inferior vena cava (D) Leftventricle (E) Mesenteric artery
The answer is A: Abdominal aorta. In patients with severe aortic atherosclerosis, embolization of atheromatous debris into the renal arteries and vascular tree may cause acute renal failure. Cholesterol clefts are observed in the photomicrograph shown. None of the other choices are sources of renal athero- emboli. Diagnosis: Renal infarct, arterial embolism
A 25-year-old woman delivers a healthy baby at 39 weeks of gestation. Six hours later, the mother develops severe short- ness of breath and appears cyanotic. Despite resuscitation, she dies 2 hours later. A section of lung at autopsy is shown in the image. These pathologic findings are associated with which of the following mechanisms of disease? (A) Amnioticfluidembolism (B) Cardiogenic shock (C) Maternal-fetalhistoincompatibility (D) Metastatic squamous cell carcinoma (E) Pulmonary thromboembolism
The answer is A: Amniotic uid embolism. Amniotic fluid embolism refers to the entry of amniotic fluid containing fetal cells and debris into the maternal circulation through open uterine and cervical veins. It is a rare maternal complication of childbirth, but when it occurs, it is often catastrophic. This disorder usually occurs at the end of labor when the pul- monary emboli are composed of the epithelial constituents (squamae) contained in the amniotic fluid. None of the other choices show these pathologic findings. Diagnosis: Amniotic fluid embolism
A 22-year-old woman delivers a baby at 29 weeks of gestation. Shortly after birth, the neonate becomes short of breath. The neonate is placed on a ventilator, but dies of respiratory insuf- ficiency. The brain at autopsy is shown. Which of the follow- ing mechanisms of disease best explains this complication of respiratory distress syndrome (RDS) of the neonate? (A) Anoxic injury (B) Birth trauma (C) Chronic passive congestion (D) Hemolytic anemia (E) Hypertension
The answer is A: Anoxic injury. The pathogenesis of RDS of the newborn is intimately linked to a deficiency of surfac- tant. This material lowers the surface tension of the alveoli at low lung volumes and thereby prevents collapse (atelecta- sis) of the alveoli during expiration. Atelectasis secondary to surfactant deficiency results in perfused but not venti- lated alveoli, a situation that leads to hypoxia and acido- sis. Intraventricular cerebral hemorrhage is a major compli- cation of RDS. The periventricular germinal matrix in the newborn brain is particularly vulnerable to hemorrhage because the dilated, thin-walled veins in this area rupture easily (see photograph). The pathogenesis of this complica- tion is believed to reflect anoxic injury to the periventricular capillaries, venous sludging and thrombosis, and impaired vascular autoregulation. Despite advances in neonatal inten- sive care, the overall mortality of RDS is about 15%, and one third of infants born before 30 weeks of gestational age die of this disorder. Although the other choices are associated with bleeding, they are unlikely causes of periventricular hemorrhage in a baby with RDS. Diagnosis: Respiratory distress syndrome of the neonate
A 50-year-old woman presents with fatigue and shortness of breath. Physical examination shows evidence of pulmonary edema, enlargement of the left atrium, and calcification of the mitral valve. A CT scan demonstrates a large obstructing mass in the left atrium. Before open heart surgery can be performed to remove the tumor, the patient suffers a stroke and expires. Which of the following hemodynamic disorders best explains the pathogenesis of stroke in this patient? (A) Arterialembolism (B) Atherosclerosis (C) Cardiogenicshock (D) Hypertensivehemorrhage (E) Septic shock
The answer is A: Arterial embolism. Cardiac myxoma is the most common primary tumor of the heart. One third of patients with a left atrial or left ventricular myxoma die from tumor embolization to the brain. Less likely causes of stroke in this patient with a cardiac myxoma include atherosclerosis (choice B) and hypertensive hemorrhage (choice D). Diagnosis: Cardiac myxoma
A 50-year-old alcoholic is rushed to the hospital with bleed- ing esophageal varices and expires. At autopsy, the patient's protruding abdomen is found to contain a large volume of serous fluid. What is the appropriate term used to describe this fluid? (A) Ascites (B) Exudate (C) Hemorrhage (D) Hydrothorax (E) Lymphedema
The answer is A: Ascites. A protruding belly and fluid accu- mulation in patients with cirrhosis represents ascites (i.e., accumulation of serous fluid in the abdominal cavity). It is primarily a consequence of portal hypertension and hypoal- buminemia. None of the other choices describe serous fluid accumulation in the abdomen. Diagnosis: Cirrhosis, portal hypertension
A 68-year-old man develops sudden, severe substernal chest pain. Laboratory studies and ECG confirm an acute myocar- dial infarct. Despite vigorous therapy, the patient cannot main- tain his blood pressure and expires 24 hours later. A cross section of the left ventricle is examined at autopsy (shown in the image). The arrows point to a soft, yellow area of necrosis. Which of the following was the most likely cause of death? (A) Cardiogenicshock (B) Hypovolemic shock (C) Neurogenicshock (D) Septicshock (E) Pulmonary edema
The answer is A: Cardiogenic shock. Cardiogenic shock is caused by myocardial pump failure. This condition usually arises as a result of a large myocardial infarction, but myo- carditis may also be responsible. Conditions that prevent left or right heart filling reduce cardiac output, resulting in obstructive shock. Such conditions include pulmonary embo- lism, cardiac tamponade, and (rarely) atrial myxoma. The other choices do not reflect a loss of cardiac output secondary to the loss of myocardial tissue owing to ischemia. Diagnosis: Acute myocardial infarction
A 42-year-old woman undergoes a face lift. Two days later, she presents for follow-up care with confluent bluish hemorrhages in the skin around her eyes ("black eyes"). Which of the follow- ing best describes this pattern of superficial skin hemorrhage? (A) Ecchymosis (B) Hematocephalus (C) Maculopapularrash (D) Petechiae (E) Purpura
The answer is A: Ecchymosis. Ecchymosis is a larger superfi- cial hemorrhage in the skin. Following hemorrhage, the initially purple discoloration of the skin turns green and then yellow before resolving. This sequence of events reflects the progres- sive oxidation of bilirubin released from the hemoglobin of degraded erythrocytes. A "black eye" is a good example of an ecchymosis. Petechiae (choice D) are pinpoint hemorrhages, usually in the skin or conjunctiva. Purpura (choice E) is a dif- fuse superficial hemorrhage in the skin up to 1 cm in diameter. Diagnosis: Ecchymosis
A 23-year-old man with hemophilia is recently wheelchair bound. Which of the following best accounts for this develop- ment? (A) Hemarthrosis (B) Hematemesis (C) Hematocephalus (D) Hematochezia (E) Hemoptysis
The answer is A: Hemarthrosis. Hemarthrosis refers to bleed- ing into the joint cavity. It is associated with joint swelling and is a crippling complication of hemophilia. Repeated bleeding may cause deformities and may limit the mobility of the joints. Hematemesis (choice B) is vomiting blood. Hematocephalus (choice C) is an intracranial infusion of blood. Hematochezia (choice D) is passage of blood caused by lower gastrointestinal hemorrhage. Hemoptysis (choice E) is coughing up blood. Diagnosis: Hemophilia, hemarthrosis
A 67-year-old man presents with sudden left leg pain, absence of pulses, and a cold limb. His past medical history is signifi- cant for coronary artery disease and a small aortic aneurysm. Which of the following is most likely responsible for develop- ment of a cold limb in this patient? (A) Acute myocardial infarction (B) Arterial thromboembolism (C) Cardiogenic shock (D) Deep venous thrombosis (E) Ruptured aortic aneurysm
The answer is B: Arterial thromboembolism. Embolism of an artery of the leg leads to sudden pain, absence of pulses, and a cold limb. In some cases, the limb must be amputated. None of the other choices would cause this clinical presenta- tion. Ruptured aortic aneurysm (choice E) presents with pain, shock, and a pulsatile mass in the abdomen. Diagnosis: Arterial thromboembolism
A 68-year-old man with ischemic heart disease and a history of smoking complains of increasing shortness of breath. On physical examination, the patient has swollen legs, an enlarged liver, and fluid in the pleural spaces (bubbly rales are heard on oscultation). Which of the following hemodynamic disorders explains the pathogenesis of hepatomegaly in this patient? (A) Arterialthromboembolism (B) Chronic passive congestion (C) Deep venous thrombosis (D) Multiple hepatic infarcts (E) Thrombosis of the hepatic vein
The answer is B: Chronic passive congestion. A generalized increase in venous pressure, typically from chronic heart fail- ure, results in an increase in the volume of blood in many organs (e.g., liver, spleen, and kidneys). The liver is partic- ularly vulnerable to chronic passive congestion because the hepatic veins empty into the vena cava immediately inferior to the heart. Budd-Chiari syndrome (thrombosis of the hepatic vein; choice E) may cause hepatomegaly, but it is not a com-plication of congestive heart failure. Diagnosis: Congestive heart failure, nutmeg liver
A 78-year-old woman dies in her sleep. A Prussian blue stain of the lungs at autopsy is shown in the image. Which of the follow- ing is the most likely cause of these histopathologic findings? (A) Acute myocardial infarction (B) Congestive heart failure (C) Diffuse alveolar damage (D) Hereditaryhemochromatosis (E) Pulmonary infarction
The answer is B: Congestive heart failure. Chronic failure of the left ventricle constitutes an impediment to the exit of blood from the lungs and leads to chronic passive congestion of the lungs. The pressure in the alveolar capillaries increases, and the vessels become engorged with blood. Microhemorrhages release erythrocytes into the alveolar spaces, where they are degraded by alveolar macrophages. The released iron, in the form of hemosiderin, remains in the macrophages, which are then labeled "heart failure cells." None of the other choices are consistent with chronic microhemorrhages in the lung. Diagnosis: Congestive heart failure
A 1-year-old girl is brought to the emergency room by her parents who report she has had a fever and diarrhea for 3 days. Her tem- perature is 38°C (101°F). The CBC shows a normal WBC count and increased hematocrit (48 g/dL). Which of the following is the most likely cause of increased hematocrit in this patient? (A) Acute phase response (B) Dehydration (C) Diabetes insipidus (D) Malabsorption (E) Septic shock
The answer is B: Dehydration. Increased hematocrit in this patient reflects hemoconcentration caused by dehydration, secondary to diarrhea. This hematologic condition, termed relative polycythemia, is characterized by decreased plasma volume with a normal red cell mass. When patients suffer from burns, vomiting, excessive sweating, or diarrhea, they not only lose fluid but also suffer electrolyte disturbances. Systemic blood pressure falls with continuous dehydration, and declining perfusion eventually leads to death. Diabetes insipidus (choice C) may cause dehydration but is an unlikely choice because the patient has a history of diarrhea. None of the other choices cause relative polycythemia. Diagnosis: Dehydration, relative polycythemia
If the patient described in Question 11 had survived the acute episode of cyanosis and shock, she would have been at risk for developing which of the following life-threatening complica- tions? (A) Bacterialendocarditis (B) Disseminated intravascular coagulation (C) Fatembolism (D) Neurogenicshock (E) Septic shock
The answer is B: Disseminated intravascular coagulation (DIC). The clinical presentation of amniotic fluid embolism can be dramatic, with the sudden onset of cyanosis and shock, followed by coma and death. If the mother survives the acute episode, she may die of DIC. Should she overcome this com- plication, she is at risk of developing acute respiratory dis- tress syndrome. DIC is a thrombotic microangiopathy. Fibrin thrombi form in small blood vessels because of uncontrollable coagulopathy, which consumes fibrin and other coagulation factors. Once coagulation factors are depleted, uncontrollable hemorrhage ensues. None of the other choices are complica- tions of amniotic fluid embolism. Diagnosis: Amniotic fluid embolism
An autopsy of a 70-year-old woman reveals a subendocardial, circumferential infarct of the left ventricle. This type of infarct is most commonly associated with which of the following? (A) Deep venous thrombosis (B) Hypotensive shock (C) Pericardial tamponade (D) Thrombotic occlusion of the right coronary artery (E) Thrombotic occlusion of the circumflex artery
The answer is B: Hypotensive shock. Myocardial infarcts are described as transmural (through the entire wall) or subendo- cardial. A transmural infarct results from complete occlusion of a major extramural coronary artery. Subendocardial infarc- tion reflects prolonged ischemia caused by partially occlud- ing lesions of the coronary arteries when the requirement for oxygen exceeds the supply. Such a situation prevails in disor- ders such as shock, anoxia, or severe tachycardia. Thrombotic occlusion (choices D and E) is more likely to cause transmural myocardial infarcts. Diagnosis: Myocardial infarction
A 9-month-old infant is brought to the emergency room with a 3-hour history of intense abdominal pain and bloody diar- rhea. Physical examination reveals a tender abdomen without ascites. The child dies 24 hours later, and torsion (volvulus) of the small bowel is discovered at autopsy. The small bowel appears dilated and hemorrhagic (shown in the image). Which of the following best describes these pathologic findings? (A) Ecchymosis (B) Infarct (C) Petechia (D) Purpura (E) Ulcer
The answer is B: Infarct. Volvulus is an example of intestinal obstruction in which a segment of gut twists on its mesen- tery, thereby kinking the bowel and usually interrupting the blood supply. Ischemia leads to infarction and intestinal gan- grene (this case). Volvulus is virtually always a consequence of an underlying congenital abnormality. Defective intestinal rotation in fetal life leads to abnormal positions of the small intestine and colon, anomalous attachments, and bands. The clinical importance of such rotational anomalies lies in their propensity to cause catastrophic volvulus of the small and large intestine and incarceration of the bowel in an internal hernia. Malrotation of the bowel permits undue mobility of the bowel loops and predisposes to midgut volvulus. When the cecum or right colon is invested with a mesentery rather than being retroperitoneal, the result may be cecal volvulus. An unusually long sigmoid colon, which occurs sometimes in patients with idiopathic constipation, permits the devel- opment of sigmoid volvulus. Meconium ileus in babies with cystic fibrosis may be complicated by volvulus and intestinal atresia. Ecchymosis (choice A), petechia (choice C), and pur- pura (choice D) represent hemorrhages of various sizes in the skin. Diagnosis: Volvulus, ischemic colitis
A 19-year-old woman complains of swelling of her eyelids, abdomen, and ankles. At bedtime, there are depressions in her legs at the location of the elastic in her socks. A chest X-ray shows bilateral pleural effusions. Urine protein electrophoresis demonstrates 4+ proteinuria. A percutaneous needle biopsy of the kidney establishes the diagnosis of minimal change neph- rotic syndrome. Soft tissue edema in this patient is most likely caused by which of the following mechanisms of disease? (A) Activehyperemia (B) Chronic passive congestion (C) Decreased intravascular oncotic pressure (D) Hyperalbuminemia (E) Increased capillary permeability
The answer is C: Decreased intravascular oncotic pressure. The pressure differential between the intravascular and the intersti- tial compartments is largely determined by the concentration of plasma proteins, especially albumin. Any condition that lowers plasma albumin levels, whether from albuminuria in nephrotic syndrome or reduced albumin synthesis in chronic liver disease, tends to promote generalized edema. Diagnosis: Minimal change nephrotic syndrome
A 60-year-old man who is recovering from surgery to correct an abdominal aneurysm suddenly develops acute chest pain and dies. A thromboembolus at the bifurcation of the left and right pulmonary arteries is noted at autopsy (shown in the image). Which of the following is the most likely cause of this patient's pulmonary embolus? (A) Bacterial endocarditis (B) Complicated atherosclerotic plaque (C) Deep venous thrombosis (D) Paradoxical embolization (E) Right ventricular mural thrombus
The answer is C: Deep venous thrombosis. One of the most tragic calamities complicating hospitalization is the sudden death of a patient who appeared to be on the way to recov- ery. The cause of this catastrophe is often massive pulmo- nary embolism. A large pulmonary embolus may lodge at the bifurcation of the main pulmonary artery (saddle embolus), obstructing blood flow to both lungs. With acute obstruction of more than half of the pulmonary arterial tree, the patient experiences severe hypotension and may die within minutes. The other choices are causes of arterial embolism. Diagnosis: Pulmonary thromboembolism
A 22-year-old construction worker falls 30 ft and fractures several bones, including his femoral shafts. Six hours later, the patient develops shortness of breath and cyanosis. Which of the following hemodynamic disorders best explains the pathogenesis of shock in this patient? (A) Acute myocardial infarction (B) Deep venous thrombosis (C) Fatembolism (D) Paradoxicalembolism (E) Septic shock
The answer is C: Fat embolism. Fat emboli originate from adipose tissue in the medulla of fractured long bones. Fat carried by venous blood reaches the lungs, filters through the pulmonary circulation, enters arterial blood, and is disseminated throughout the body. The occlusion of cerebral capillaries is accompanied by petechial hemorrhages in the brain and is the most important complication of fat embolism. Acute myocardial infarction (choice A) would be unlikely in a 22-year-old patient. Deep venous thrombosis (choice B) and septic shock (choice E) would be unlikely within this time frame. Paradoxical embolism (choice D) refers to emboli that arise in the venous circulation and bypass the lungs by traveling through an incompletely closed foramen ovale, subsequently entering the arterial circulation. Diagnosis: Fat embolism
A 69-year-old man is brought to the emergency room complaining of visual difficulty and weakness. On physical examination, the patient is aphasic with a right-sided hemiplegia. Retinal hemorrhages are seen bilaterally. You suspect that a thromboembolus coursed to the left middle cerebral artery and smaller emboli traveled to the retinal arteries. Which of the following anatomic sites is the most likely source for these emboli in this patient? (A) Adrenals (B) Deep leg veins (C) Heart (D) Liver (E) Lungs
The answer is C: Heart. The heart is the most common source of arterial thromboemboli, which usually arise from mural thrombi or diseased valves. These emboli tend to lodge at points where the vessel lumen narrows abruptly (e.g., at bifurcations or in the area of an atherosclerotic plaque). The viability of the tissue supplied by the vessel depends on the availability of collateral circulation and on the fate of the embolus itself. Paradoxical emboli from the right side of the circulation are exceedingly rare. Diagnosis: Cerebral embolism, stroke
A 76-year-old woman is brought to the emergency department because of the sudden onset of two episodes of hemoptysis and left-sided chest pain, which is exacerbated upon inspira- tion. Her temperature is 38°C (101°F), pulse 110 per minute, respirations 35 per minute, and blood pressure 158/100 mm Hg. The patient is admitted, but suffers a massive stroke and expires 48 hours later. Autopsy reveals a pulmonary infarct in upper segments of the lower lobe (shown in the image). Which of the following best explains the color of this patient's pulmonary infarct? (A) Accumulation of hemosiderin-laden macrophages (B) Development of bronchopneumonia (C) Hemorrhage from bronchial arteries (D) Organization of a pulmonary thromboembolus (E) Passive congestion of bronchopulmonary segments
The answer is C: Hemorrhage from bronchial arteries. The gross and microscopic appearance of an infarct depends on its location and age. Pale infarcts are typically seen in the heart, kidneys, and spleen. Red infarcts may result from either arte- rial or venous occlusion. They are distinguished from pale infarcts by bleeding into the necrotic area from adjacent arter- ies and veins. Red infarcts occur principally in organs with a dual blood supply, such as the lung, or those with extensive collateral circulation, such as the small intestine and brain. In the heart, a red infarct occurs when the infarcted area is reperfused, as may occur following spontaneous or thera- peutically induced lysis of the occluding thrombus. Grossly, red infarcts are sharply circumscribed, firm, and dark red to purple. Over a period of several days, acute inflammatory cells infiltrate the necrotic area from the viable border. The cellular debris is phagocytosed and digested by polymorpho- nuclear leukocytes and later by macrophages. Granulation tissue eventually forms, to be replaced ultimately by a scar. None of the other choices would cause hemorrhage into an infarct. Diagnosis: Pulmonary infarction, pulmonary thromboembolism
A 62-year-old man with a history of hypertension is rushed to the emergency room with severe "tearing pain" of the anterior chest. His blood pressure is 80/50 mm Hg. Physical examination shows pallor, diaphoresis, and a murmur of aortic regurgitation. Laboratory studies and ECG show no evidence of acute myocardial infarction. Four hours later, the patient goes into cardiac arrest. An ECG reveals electromechanical dissociation. Which of the following best explains the pathogenesis of cardiac tamponade in this patient? (A) Disseminated intravascular coagulation (B) Embolism (C) Hemorrhage (D) Passivehyperemia (E) Thrombosis
The answer is C: Hemorrhage. Pericardial fluid may accu- mulate rapidly, particularly with hemorrhage caused by a ruptured myocardial infarct, dissecting aortic aneurysm (seen in this patient), or trauma. In these circumstances, the pressure in the pericardial cavity exceeds the filling pressure of the heart, a condition termed cardiac tamponade. The term "electromechanical dissociation" refers to a heart rhythm that should produce a pulse, but does not. The most common cause of this condition is hypovolemia. The resulting precipitous decline in cardiac output is often fatal. The pathogenesis of dissecting aortic aneurysm in most instances can be traced to a weakening of the aortic media (cystic medial necrosis). Most patients have a history of hypertension. Disseminated intravascular coagulation (choice A) refers to widespread ischemic changes secondary to microvascular thrombi. Passive hyperemia (choice D) refers to the engorgement of an organ with venous blood. Diagnosis: Dissecting aortic aneurysm
A 50-year-old fire fighter emerges from a burning house with third-degree burns over 70% of his body. The patient expires 24 hours later. Which of the following was the most likely cause of death? (A) Congestive heart failure (B) Disseminated intravascular coagulation (C) Hypovolemic shock (D) Pulmonary saddle embolism (E) Toxic shock syndrome
The answer is C: Hypovolemic shock. Hypovolemic shock may be caused by hemorrhage, fluid loss from severe burns, diarrhea, excessive urine formation, perspiration, or trauma. In the case of burns or trauma, direct damage to the micro- circulation increases vascular permeability. Persons with third-degree burns weep large amounts of plasma. The other choices are unlikely causes of death in an acute burn victim. Diagnosis: Hyperthermia, hypovolemic shock
An 80-year-old woman with a history of hypertension is rushed to the emergency room complaining of chest pain of 1-hour duration. Physical examination discloses bilateral pit- ting leg edema, hepatosplenomegaly, and rales at the bases of both lungs. The patient is apprehensive and sweating. The patient loses consciousness and dies of a cardiac arrhythmia. Microscopic examination of the lungs at autopsy is shown. Which of the following hemodynamic processes best explains this pathologic finding? (A) Decreased capillary permeability (B) Decreased intravascular oncotic pressure (C) Increased intravascular hydrostatic pressure (D) Increased intravascular oncotic pressure (E) Vasoconstriction of precapillary arterioles
The answer is C: Increased intravascular hydrostatic pressure. In patients with congestive heart failure, venous engorge- ment of the lung leads to accumulation of a transudate in the alveoli. Chronic left ventricle failure impedes blood flow out of the lungs and leads to passive pulmonary congestion. As a result, pressure in the alveolar capillaries increase (increased hydrostatic pressure) and these vessels become engorged with blood. Increased pressure forces fluid from the blood into the alveolar spaces, resulting in pulmonary edema, which inter- feres with gas exchange. The photomicrograph shows pink staining fluid in the alveoli. None of the other choices cause pulmonary edema in patients with congestive heart failure. Diagnosis: Pulmonary edema, congestive heart failure
A 58-year-old woman is brought to the emergency department 4 hours after vomiting blood and experiencing bloody stools. The patient was diagnosed with alcoholic cirrhosis 2 years ago. Endoscopy reveals large esophageal varices, one of which is actively bleeding. Which of the following best explains the pathogenesis of dilated esophageal veins in this patient? (A) Decreased intravascular oncotic pressure (B) Increased capillary permeability (C) Increased intravascular hydrostatic pressure (D) Vasoconstriction of arterioles (E) Vasodilatation of capillaries
The answer is C: Increased intravascular hydrostatic pressure. This patient with alcoholic cirrhosis has portal hypertension (increased hydrostatic pressure) and bleeding esophageal varices. Massive hematemesis is a frequent cause of death in patients with esophageal varices. Decreased intravascular oncotic pressure (choice A) contributes to the development of ascites in patients with cirrhosis but not to the development of esophageal varices. Diagnosis: Esophageal varices, hematemesis
A 21-year-old pregnant woman experiences abruptio placentae at 37 weeks of gestation and develops severe vaginal bleeding that is difficult to control. Five months later, the patient presents with profound lethargy, pallor, muscle weakness, failure of lactation, and amenorrhea. Which of the following best explains the pathogenesis of pituitary insufficiency in this patient? (A) Abscess (B) Embolism (C) Infarction (D) Passivehyperemia (E) Thrombosis
The answer is C: Infarction. Hypotension caused by post- partum bleeding can, in rare cases, lead to infarction of the pituitary. The pituitary is particularly susceptible at this time because its enlargement during pregnancy renders it vulnerable to a reduction in blood flow. None of the other choices cause clinical features of pan-hypopituitarism. Diagnosis: Sheehan syndrome, pituitary infarction
A 50-year-old woman appears at your office. She was sub- jected to radical mastectomy and axillary node dissection for breast cancer a year ago. She now notices that her arm becomes swollen by the end of the day. What is the appropri- ate name for this fluid accumulation? (A) Chylothorax (B) Hydrothorax (C) Lymphedema (D) Purulentexudate (E) Fibrinous exudate
The answer is C: Lymphedema. Obstruction of lymphatic flow may occur in a number of clinical settings, but is most common because of surgical removal of lymph nodes or tumor obstruction. For example, the lymphatic system may be obstructed after axillary lymph node dissection for breast can- cer. Prolonged lymphatic obstruction in the patient's shoul- der causes edema, progressive dilation of lymphatic vessels (lymphangiectasia), and overgrowth of fibrous tissue. Lymp- hangiosarcoma has also been described. Chylothorax (choice A) represents an accumulation of lymphedema in the pleural space. Exudates (choices D and E) are associated with acute inflammation. Diagnosis: Lymphedema, breast cancer
Histologic examination of the heart in the patient described in Question 31 shows extensive growth of fibroblasts and depo- sition of collagen in the mural thrombus. Which of the follow- ing terms describes this outcome of thrombosis? (A) Canalization (B) Hyalinization (C) Organization (D) Propagation (E) Regeneration
The answer is C: Organization. Once formed, arterial thrombi may undergo (1) lysis, (2) propagation, (3) organization, (4) canalization, or (5) embolization. Organization refers to the invasion of connective tissue elements, which causes a throm- bus to become firm and appear grayish white. Canalization (choice A) is the process by which new lumina lined by endothelial cells form within an organized thrombus. Propa- gation (choice D) implies an increase in size. Diagnosis: Mural thrombus
A 20-year-old man is brought to the emergency room after rupturing his spleen in a motorcycle accident. His blood pres- sure on admission is 80/60 mm Hg. Analysis of arterial blood gasses demonstrates metabolic acidosis. This patient is most likely suffering from which of the following conditions? (A) Acute pancreatitis (B) Cardiogenic shock (C) Hypersplenism (D) Hypovolemic shock (E) Septic shock
The answer is D: Hypovolemic shock. Hypovolemic shock is secondary to a pronounced decrease in blood or plasma vol- ume, caused by the loss of fluid from the vascular compart- ment. Hemorrhage, fluid loss from severe burns, diarrhea, excessive urine formation, perspiration, and trauma are major mechanisms of fluid loss that can lead to hypovolemic shock. Cardiogenic shock (choice B) is caused by myocardial pump failure. Septic shock (choice E) is improbable in this setting. Diagnosis: Hypovolemic shock
A 33-year-old woman presents with black stools. Labora- tory studies demonstrate a hypochromic, microcytic anemia. Upper GI endoscopy reveals a duodenal ulcer. Which of the following best describes the stools in this patient with peptic ulcer disease? (A) Hematemesis (B) Hematobilia (C) Hematochezia (D) Melena (E) Steatorrhea
The answer is D: Melena. Melena (black stool) is a symp- tom of upper gastrointestinal bleeding. Blood from ruptured esophageal varices or a peptic ulcer is partially digested by hydrochloric acid. Hemoglobin is transformed into a black pigment (hematin), which imparts a typical "coffee-grounds" color to the stool. Hematemesis (choice A) is vomiting of blood. Hematobilia (choice B) is bleeding into the biliary pas- sages, as a complication of trauma or neoplasia. Hematochezia (choice C) is passage of bloody stools caused by lower gas- trointestinal hemorrhage. Steatorrhea (choice E) is passage of fatty stools caused by pancreatic disease and malabsorption. Diagnosis: Peptic ulcer disease
A 63-year-old man suffers a massive stroke and expires. At autopsy, the pathologist finds a laminated thrombus adher- ent to the wall of the left ventricle (shown in the image). Which of the following is the most likely cause of this autopsy finding? (A) Atrialfibrillation (B) Bacterial endocarditis (C) Maranticendocarditis (D) Myocardialinfarction (E) Viral myocarditis
The answer is D: Myocardial infarction. Myocardial infarction is the most common cause of mural thrombi in the left ven- tricle. These mural thrombi are a common source of arterial thromboemboli. Such emboli may occlude cerebral arteries and cause cerebral infarcts, known clinically as strokes. Atrial fibrillation (choice A) predisposes to the formation of mural thrombi in that location. Diagnosis: Mural thrombus
A 40-year-old man with a history of bacterial endocarditis notices numerous pinpoint hemorrhages around the orbit of his eyes (shown in the image; see arrows). What is the appropriate term used to describe this form of superficial hemorrhage? (A) Ecchymosis (B) Erythema (C) Hyperemia (D) Petechia (E) Purpura
The answer is D: Petechia. Petechiae are pinpoint hem- orrhages, usually in the skin or conjunctiva. This lesion represents the rupture of a capillary or arteriole and occurs in conjunction with vasculitis and coagulopathy. Petechiae may also be produced by microemboli from infected heart valves (bacterial endocarditis). Hyperemia (choice C) refers to increased blood in a tissue or organ. Erythema (choice B) is inflammatory redness of the skin. Ecchymosis (choice A) is a larger superficial hemorrhage in the skin. Purpura (choice E) is a diffuse superficial hemorrhage in the skin up to 1 cm in diameter. Diagnosis: Endocarditis, petechia
The body of a 28 year old homeless man is brought to the coroner's office. Histologic examination of the lungs under polarized light is shown. Which of the following is the most likely cause of the birefringence observed in this pulmonary lesion? (A) Alcoholism (B) Aspiration of mineral oil (C) Bacterial pneumonia (D) Cocaine abuse (E) Intravenous drug use
The answer is E: Intravenous drug use. Embolism is the pas- sage through the venous or arterial circulations of any material capable of lodging in a blood vessel and, thereby, obstructing its lumen. Intravenous drug abusers who use talc as a carrier for illicit drugs may introduce it into the lung via the blood- stream (i.e., venous embolism). None of the other choices exhibit birefringence under polarized light. Diagnosis: Pulmonary embolism, talc embolism
A 23-year-old woman complains of a recent onset of yellowing of her skin and increasing abdominal girth. Physical examina- tion reveals jaundice and ascites. Ultrasound examination of her abdomen demonstrates thrombosis of the hepatic veins. A liver biopsy discloses severe sinusoidal dilation within the centrilobular regions. This pathologic finding is caused by which of the following hemodynamic disorders? (A) Activehyperemia (B) Arterial embolism (C) Hematoma (D) Hemorrhage (E) Passive hyperemia
The answer is E: Passive hyperemia. Passive hyperemia (chronic passive congestion) may be confined to a limb or an organ as a result of localized obstruction to venous drainage. Examples include deep venous thrombosis of the leg veins, with resulting edema of the lower extremity, and thrombosis of the hepatic veins (Budd-Chiari syndrome, this patient) with secondary chronic passive congestion of the liver. Active hype- remia (choice A) is an augmented supply of blood to an organ, usually as a physiologic response to an increased functional demand. The most striking active hyperemia occurs in asso- ciation with inflammation. Arterial embolism (choice B) typi- cally causes infarction. Hematoma (choice C) and hemorrhage (choice D) represent extravascular accumulation of blood. Diagnosis: Budd-Chiari syndrome
A 72-year-old woman complains of shortness of breath on exertion. She states that she also becomes short of breath at night unless she uses three pillows (orthopnea). Physical examination reveals mild obesity, bilateral pitting leg edema, an enlarged liver and spleen, and fine crackling sounds on inspiration (rales). A chest X-ray shows cardiomegaly. What is the most likely cause of orthopnea in this patient? (A) Asthma (B) Cardiac tamponade (C) Emphysema (D) Hypovolemicshock (E) Pulmonary edema
The answer is E: Pulmonary edema. Patients in left-sided congestive heart failure complain of shortness of breath (dys- pnea) on exertion and when recumbent (orthopnea). They may be awakened from sleep by sudden episodes of shortness of breath (paroxysmal nocturnal dyspnea). Physical exami- nation usually reveals distended jugular veins. Persons with right-sided failure have pitting edema of the lower extremities and an enlarged and tender liver. Patients in congestive heart failure with pulmonary edema have crackling breath sounds (rales) caused by the expansion of fluid-filled alveoli. Cardiac tamponade (choice B) occurs when the pressure in the peri- cardial cavity rises to exceed the filling pressure of the heart. Orthopnea is not a feature of the other choices. Diagnosis: Congestive heart failure
A 92-year-old woman is brought unconscious to the emergency room from a nursing home. Her blood pressure is 70/30 mm Hg. She is febrile (38°C/100.5°F) and tachypneic. Laboratory studies demonstrate a WBC count of 22,000/μL with 92% neutrophils. Urinalysis reveals numerous Gram-negative organisms. Which of the following most likely accounts for this patient's signs and symptoms? (A) Anaphylacticshock (B) Cardiogenic shock (C) Hypovolemicshock (D) Neurogenicshock (E) Septic shock
The answer is E: Septic shock. Septic shock results from a systemic inflammatory response syndrome that leads to mul- tiple organ dysfunction and hypotension. Clinical features include two or more signs of systemic inflammation (e.g., fever, tachycardia, tachypnea, leukocytosis, or leukopenia) in the setting of a known cause of inflammation. These processes often progress to multiple organ dysfunction syndrome in crit- ically ill patients. Septicemia with Gram-negative organisms is the most common cause of septic shock. Anaphylactic shock (choice A) occurs as a consequence of a systemic type I hyper- sensitivity reaction. Neurogenic shock (choice D) can follow acute injury to the brain or spinal cord, which impairs the neural control of vasomotor tone, leading to generalized vaso- dilation. Cardiogenic shock (choice B) is a feature of advanced heart failure. Hypovolemic shock (choice C) occurs following blood loss. Diagnosis: Septic shock
The patient described in Question 13 suffers a massive heart attack and expires. Microscopic examination of the liver at autopsy would most likely reveal which of the following his- topathologic changes? (A) Diffuse hydropic degeneration (B) Large iron deposits within hepatocytes (C) Massive hepatic necrosis (D) Regenerating hepatic nodules surrounded by fibrous bands (E) Sinusoids dilated with blood
The answer is E: Sinusoids dilated with blood. In patients with chronic passive congestion of the liver, the central veins of the hepatic lobule become dilated. The increased venous pressure leads to dilation of the sinusoids and pressure atro- phy of the centrilobular hepatocytes. Grossly, the cut surface of the chronically congested liver exhibits dark foci of centri- lobular congestion surrounded by paler zones of unaffected peripheral portions of the lobules. The result resembles a cross section of a nutmeg and is appropriately called nutmeg liver. Longstanding passive congestion leads to bridging fibrosis; however, only in the most extreme cases is the fibrosis suf- ficiently severe to justify the label cardiac cirrhosis (choice D). None of the other choices are associated with congestive heart failure. Diagnosis: Congestive heart failure, nutmeg liver
A 53-year-old man is hospitalized after injuring his neck in an automobile accident. He is placed in cervical traction. One week later, the patient develops painful swelling and erythema of his left calf. Doppler imaging discloses deep venous throm- bosis. Which of the following is the most likely cause for the development of thrombosis in this patient? (A) Age (B) Endothelial damage (C) Hypercoagulability (D) Infection (E) Stasis
The answer is E: Stasis. Venous thrombosis is caused by the same factors that predispose to arterial thrombosis, namely endothelial injury, stasis, and a hypercoagulable state. Although all of the choices are risk factors for deep venous thrombosis, the most likely choice, given the patients' immobilization, is stasis. Most venous thromboses occur in the deep veins of the legs. Diagnosis: Deep venous thrombosis
A 69-year-old retired man is brought to the emergency department because of the sudden onset of left-sided chest pain, which is exacerbated upon inspiration. Physical examination reveals dyspnea and hemoptysis. His temperature is 38°C (101°F), pulse 110 per minute, respirations 35 per minute, and blood pressure 158/100 mm Hg. A lateral chest wall friction rub is present on auscultation. The left leg is markedly edematous with a positive Homans' sign. A chest X-ray reveals a left pleural effusion. What is the most likely cause of this patient's pulmonary condition? (A) Congestive heart failure (B) Cor pulmonale (C) Mitralstenosis (D) Subacuteendocarditis (E) Thromboembolism
The answer is E: Thromboembolism. This patient with mild congestive heart failure developed pulmonary embolism. Small pulmonary emboli rarely cause infarctions because of the dual blood supply to the lungs and because oxygen can diffuse from the alveoli into lung tissue. Symptoms depend upon the extent of blockage of the pulmonary arterial tree, whether there is already cardiopulmonary disease, and whether pulmonary infarction occurs. The other choices do not induce these pleural signs and symptoms. Diagnosis: Pulmonary thromboembolism
A 20-year-old woman presents to the emergency room com- plaining of having had a severe headache for 4 hours. Physical examination reveals numerous small red spots on the extremi- ties and a stiff neck. Her temperature is 38.7°C (103°F). Lumbar puncture returns purulent fluid, with segmented neutrophils and Gram-negative organisms resembling menin- gococci. A few hours later, the patient goes into shock and becomes comatose. Severe endothelial injury in this patient is primarily mediated by which of the following proteins? (A) α-Fetoprotein (B) IgG (C) Interferon-γ (D) Transforming growth factor-β (E) Tumor necrosis factor-α
The answer is E: Tumor necrosis factor-a (TNF-a). Septicemia with Gram-negative organisms is the most common cause of septic shock. The invading bacteria are responsible for the release of endotoxin, a lipopolysaccharide (LPS). On entry into the circulation, LPS binds to the surface of monocytes/ macrophages. The CD14 recognition complex mediates signaling through activation of nuclear transcription factor- kappa B (NF-κB) and upregulates the expression of TNF-α. In septic shock, this protein is released in great excess, resulting in effects that are often lethal. None of the other mediators cause severe injury to vascular endothelium in patients with septic shock. Diagnosis: Meningitis, septic shock
A 60-year-old man with a history of multiple myocardial infarcts is hospitalized for shortness of breath. Physical exami- nation reveals marked jugular distension, hepatomegaly, ascites, and pitting edema. A chest X-ray reveals cardiomegaly. The patient subsequently dies of cardiorespiratory failure. Examination of the lungs at autopsy would most likely dis- close which of the following pathologic changes? (A) Diffuse alveolar damage with hyaline membranes (B) Intra-alveolar purulent exudate (C) Lymphocytic interstitial pneumonitis (D) Pulmonary arteriopathy with plexiform lesions (E) Vascular congestion and hemosiderin-laden macrophages
The answer is E: Vascular congestion and hemosiderin-laden macrophages. Left ventricular failure leads to chronic passive congestion of the lungs. Blood leaks from the congested pulmo- nary capillaries into the alveoli. Alveolar macrophages degrade RBCs and accumulate hemosiderin. These hemosiderin-laden macrophages are called heart failure cells. Diffuse alveolar damage with hyaline membranes (choice A) is a feature of adult respiratory distress syndrome. Purulent exudate (choice B) is observed in bacterial pneumonia. Lymphocytic interstitial pneumonitis (choice C) is characteristic of viral pneumonitis. Plexiform lesions (choice D) are typically seen in patients with pulmonary hypertension. Diagnosis: Congestive heart failure, pulmonary edema